Automated trailer coupling arrangement

ABSTRACT

An automated trailer coupling arrangement includes a receiver member supported on a towed vehicle and including pneumatic and electrical couplers, a shuttle member including pneumatic and electrical couplers configured to couple to pneumatic and electrical supply sources and a control arm assembly supported on a towing vehicle and including a carrier member configured to operably couple and uncouple with the shuttle member, and an actuator coupled to the carrier member configured to move the carrier between a first position where the carrier member is coupled with the shuttle member and the shuttle member is spaced from the receiver member, and a second position where the second pneumatic coupler is coupled with the first pneumatic coupler and the second electrical coupler is coupled with the first electrical coupler and the carrier is uncoupled and spaced from the shuttle member.

BACKGROUND

The embodiments disclosed herein relate to an arrangement for connecting a towed vehicle to a towing vehicle, and in particular to an automated connection arrangement for connecting a semi-truck or tractor-trailer to an associated heavy-duty semi-trailer.

BRIEF SUMMARY

One embodiment as disclosed herein includes an automated trailer coupling arrangement that includes a receiver member configured to be supported on a towed vehicle and including a first pneumatic coupler and an electrical coupler, and a shuttle member including a second pneumatic coupler configured to couple to a pneumatic supply source of a towing vehicle, and a second electrical coupler configured to couple to an electrical supply source of the towing vehicle. The coupling arrangement further includes a control arm assembly configured to be supported on a towing vehicle, that includes a carrier member configured to operably couple and uncouple with the shuttle member, an actuator coupled to the carrier member configured to move the carrier between a first position where the carrier member is coupled with the shuttle member and the shuttle member is spaced from the receiver member, and a second position where the second pneumatic coupler is coupled with the first pneumatic coupler and the second electrical coupler is coupled with the first electrical coupler and the carrier is uncoupled and spaced from the shuttle member.

Another embodiment disclosed herein includes an automated trailer coupling arrangement that includes a receiver member supported on a towed vehicle and including a first pneumatic coupler, a second pneumatic coupler and an electrical coupler, and a shuttle member including a third pneumatic coupler pneumatically coupled to a pneumatic supply source of the towing vehicle, a fourth pneumatic coupler pneumatically coupled to the pneumatic support source, and a second electrical coupler coupled to an electrical supply source of the towing vehicle. The coupling arrangement further includes a control arm assembly supported on a towing vehicle that includes a carrier member configured to operably couple and uncouple with the shuttle member, and an actuator coupled to the carrier member, wherein the control arm is moveable between a first position where the carrier member is coupled with the shuttle member and the shuttle member is spaced from the receiver member, a second position where the shuttle member is received within the receiver member and is coupled to the carrier member, a third position where the shuttle member is received within the receiver member and the first and second pneumatic couplers are pneumatically coupled with the third and fourth pneumatic couplers, respectively, and the first electrical coupler is coupled with the second electrical coupler, a fourth position where the carrier member is uncoupled from the shuttle member and abuts the shuttle member, and a fifth position where the carrier member is uncoupled and spaced from the shuttle member. The coupling arrangement still further includes a controller operable coupled to the control arm and configured to move the arm between the first, second, third, fourth and fifth positions.

Yet another embodiment disclosed herein includes a method for operating an automated trailer coupling arrangement that includes providing a receiver member supported on a towed vehicle and including a first pneumatic coupler and an electrical coupler, and providing a shuttle member including a second pneumatic coupler pneumatically coupled to a pneumatic supply source of a towing vehicle, and a second electrical coupler coupled to an electrical supply source of the towing vehicle. The method further includes providing a control arm assembly coupled to a towing vehicle coupled to a towing vehicle that includes a carrier member configured to operably couple and uncouple with the shuttle member, and an actuator coupled to the carrier member, and configured to be supported from the towing vehicle, and coupling the shuttle member to the receiver by moving the control arm assembly from a first position where the carrier member is coupled with the shuttle member and the shuttle member is spaced from the receiver member, to a second position where the shuttle member is received within the receiver member and is coupled to the carrier member, to a third position where the shuttle member is received within the receiver member and the first pneumatic coupler is pneumatically coupled with the second pneumatic coupler, respectively, and the first electrical coupler is coupled with the second electrical coupler, to a fourth position where the carrier member is uncoupled from the shuttle member and abuts the shuttle member, to a fifth position wherein the carrier member is uncoupled and spaced from the shuttle member.

The embodiments as disclosed herein provide an automated trailer coupling arrangement of a robust and durable design that greatly increases the efficiency of truck/trailer operators while simultaneously improving safety relating to the coupling/uncoupling of a trailer to/from a towing vehicle. The automated trailer coupling arrangement may be utilized with manned or autonomous vehicle applications, may be retrofitted to existing vehicle platforms, is capable of a long operating life, and is particularly well adapted for the proposed use.

These and other features, advantages, and objects of the embodiments disclosed herein will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of an automated trailer coupling arrangement;

FIG. 2 is a front perspective view of the automated trailer coupling arrangement;

FIG. 3 is a rear perspective view of the automated trailer coupling arrangement;

FIG. 4 is an enlarged perspective view of an area of the automated trailer coupling arrangement with portion of cylinder arrangements shown in phantom to illustrate internal components thereof;

FIGS. 5A and 5B are front and rear perspective views of a carrier and a receiver of the automated trailer coupling arrangement;

FIG. 6 is a perspective view of a receiver of the automated trailer coupling arrangement;

FIGS. 7A and 7B are schematic side views of the automated trailer coupling arrangement shown at various coupling stages;

FIGS. 8A-8D are front elevational views of the automated trailer coupling arrangement illustrating a coupling procedure;

FIG. 9 is an enlarged cross-sectional view of a portion of the carrier, the shuttle and the receiver; and

FIGS. 10A-10D are elevational front views of the automated a trailer coupling arrangement illustrating an uncoupling procedure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in FIG. 1. However, it is to be understood that the embodiments as disclosed herein may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

The reference numeral 10 (FIG. 1) generally designates an automated connection arrangement for pneumatically and electrically coupling a towing vehicle, or semi-truck to a towed vehicle, or semi-trailer. In the illustrated example, the towing vehicle includes a pair of longitudinally-extending, C-shaped frame rails 12 while the towed vehicle includes a cargo housing or container 14 having at least a front wall 16, a pair of side walls 18, and a bottom wall 20. The embodiments of the automated connection arrangement 10 may also be utilized with vehicles having other configurations including commercial and light-duty vehicles.

In the illustrated example, the connection arrangement 10 includes an automated placer assembly 22 (FIGS. 1-3), and a carrier 24 and a shuttle 26 configured to be manipulated and placed by the placer arrangement 22, and a receiver 28 fixedly secured to the front wall 16 of the cargo housing 14 of the trailer and configured to receive and couple with the shuttle 26.

The placer assembly 22 includes a mounting assembly 30 including a mounting member 32 configured to be secured to a vertical portion 34 (FIG. 1) of one of the frame rails 12, and a C-shaped mounting bracket 36 pivotably coupled to the mounting member 32 via a pair of pivot pins 38 of the mounting member 32 received within a pair of corresponding bores 40 of the mounting bracket 36 and pivotable about an axis 42. The mounting bracket 36 comprises a pair of pivot blocks 44 and a pair of side plates 46 that cooperates to provide a C-shaped cross-sectional configuration. The placer assembly 22 further includes a cylinder assembly 48 and an upper arm 50, where the cylinder assembly 48 includes a first end 52 and a second end 54 and the upper arm includes a first end 56 and a second end 58. The first end 52 of the cylinder assembly 48 and the first end 56 of the upper arm 50 are attached to the side plates 46 of the mounting bracket 36 by a pair of mechanical fasteners, such as bolts 60, 61 for pivoting about pivot axes 62, 64, respectively. The second end 54 of the cylinder assembly 48 and the second end 58 of the upper arm 50 are operably coupled to carrier 24 via a pair of pivot pins 66, 68 for pivoting about a pair of pivot axes 70, 72, respectively, where the carrier 24 is described in more detail below. In the illustrated example, the cylinder assembly 48 is driven by an internal pneumatic cylinder arrangement 73.

As best illustrated in FIG. 4, the second end 54 of the cylinder assembly 48 and the second end 58 of the upper arm 50 each include spring-biased, length-adjustment arrangements 75, 77. Specifically, the length-adjustment arrangement 75 of the cylinder assembly 48 includes an inner housing 74 telescopingly received within an outer housing 76, and a spring member 78, such as a coil spring, positioned between the inner housing 74 and the outer housing 76 and biasing the inner housing 74 from the outer housing 76 in a direction 80, while the length-adjustment arrangement 77 of the upper arm 50 includes an inner housing 82 telescopingly received within an outer housing 84 and a spring member 86, such as a coil spring, positioned between the inner housing 82 and the outer housing 84 and biasing the inner housing 82 from the outer housing 84 in a direction 88. Total travel of the inner housing 74 within the outer housing 76 is limited by a travel limiter 90 that includes a slot 92 extending through the inner housing 74 and a screw 94 that extends through the slot 92 and is threadably received within the outer housing 76, while travel of the inner housing 82 within the outer housing 84 is limited by a travel limiter 96 that includes a slot 98 extending through the inner housing 82, and a screw 100 that extends through the slot 98 and is threadably received within the outer housing 84. Travel of the inner housing 74 is limited with respect to the outer housing 76 by the screw 94 contacting the ends of the slot 92, while travel of the inner housing 82 with respect to the outer housing 84 is limited by the screw 100 contacting the ends of the slot 98.

In the illustrated example, the cylinder assembly 48, the upper arm 50, the mounting bracket 36 and the carrier 24 cooperate to form a four-bar linkage arrangement. The placer assembly 22 further includes a pair of lower control linkages 102 each having a first end 106 pivotably coupled to an associated side plate 46 of the mounting bracket 36 and a second end 108 pivotably coupled to the cylinder assembly 48 along the length thereof, and a pair of upper control linkages 104 each having a first end 110 pivotably coupled to an associated side plate 46 of the mounting bracket 36, and a second end 112 pivotably coupled to the upper arm 50 along the length thereof.

As best illustrated in FIGS. 5A and 5B, the carrier 24 includes a pair of pneumatic cylinders 114 coupled to a pneumatic input 116, where the pneumatic input 116 is connected to a controller 118 (FIG. 1) remotely located from the carrier 24, and preferably located within a cab of the associated towing semi-truck.

The shuttle 26 (FIGS. 5A and 5B) includes a housing 20 that includes a first pneumatic input port 122 pneumatically coupled to a first pneumatic output port 123, a second pneumatic input port 124 pneumatically coupled to a second pneumatic output port 125, and an electrical input connector 126 electrically coupled to an electrical output connector 127. Preferably, the first pneumatic input port 122 and the second pneumatic input port 124 are plumbed to pneumatic supply lines 132, 134 (FIG. 1) coming from and supplied pneumatic pressure by the associated towing vehicle, and an electrical supply line 136 providing electricity from the associated towing vehicle. Alternatively, each of the pneumatic input ports 122, 124 and the electrical input connector 126 could be configured to operably couple to one or more glad hands typically associated with heavy-duty semi-truck/trailer connection arrangements.

The shuttle 26 further includes a coupling assembly 138 including a pair of clamping arms 140 pivotably coupled to the housing 120 via respective pivot bolts 142. Each clamping arm 140 includes a hook 144 positioned at a distal end thereof, and a proximal actuator end 146. Each clamping arm 140 is biased toward a clamping position by an associated coil spring 148 as described below.

In the illustrated example, the receiver 28 (FIG. 6) includes a C-shaped receiver portion 152, and a triangularly-shaped guide portion 154, where the receiver portion 152 includes a pair of side walls 156 and a top wall 158, and the guide portion 154 includes a pair of side walls 160 that flare laterally outward from the side walls 156 of the receiver portion 152. The receiver 158 further includes a rear wall 162 that cooperates with the sidewalls 156 of the receiver portion 150 and the sidewalls 160 of the guide portion 154 to define a widened lower portion 164 communicating with a narrowed upper portion 166. Each of the side walls 156 of the receiver portion 152 includes a pneumatic port 168 and a relief 169, while the top wall includes an electrical port 170 for receiving an electrical connection associated with the trailer therein. The rear wall 162 includes a plurality of apertures 172 configured to receive mechanical fasteners, such as screws or bolts, therethrough for attaching the receiver 28 to the front wall 16 of the trailer.

During operation, the associated vehicle is coupled with the trailer or towed vehicle by positioning the tractor or towing vehicle with respect to the trailer such that the carrier 24 and the shuttle 26 as carried by the towing vehicle are somewhat aligned with the receiver 28 as carried by the towed vehicle. As best illustrated in FIGS. 7A, 7B and 8A-8D, the shuttle member 26 is initially carried by the carrier 24. Specifically, the pneumatic cylinders 114 of the carrier 24 are actuated via the controller 118 either by an operator or automatically by a vehicle control arrangement typically associated with automated vehicles, in an outward direction 176 such that the pneumatic cylinders 114 act against the distal end 146 of each of the clamping arms 140, thereby pivoting the clamping arms 140 about the associated pivot bolts 142 overcoming the biasing force exerted by the springs 140. As best illustrated in FIG. 9, the distal end 146 of each clamping arm 140 includes a relief 178 configured to receive a boss 180 of the associated pneumatic cylinder. The controller 118, whether manually or automatically operated, then actuates the pneumatic cylinder arrangement 173 of the cylinder assembly 48, thereby moving the carrier 24 and the shuttle 26 in an arcuate path 182. The carrier 24 and the shuttle 26 continue in the arcuate path 182 until the carrier 24 and/or the shuttle 26 abut the rear wall 162 of the receiver 28. The force exerted by the rear wall 162 on the carrier 24 and/or shuttle 26 may then force compression of the spring member 78 of the cylinder assembly 48 and the spring member 86 of the upper arm 58, such that the carrier 24 and the shuttle 26 then continue along a linear path 184. Further, should the carrier 24 and shuttle 26 be laterally misaligned with the upper portion 166 of the receiver 28, rounded upper corners 186 of the housing 120 of the shuttle 26 abut one of the angled sidewalls 160 thereby forcing the cylinder assembly 48 and the upper arm 50 to pivot about the pivot axis 42 and allowing proper alignment with and receiving of the shuttle 26 into the upper portion 166 of the receiver 28. The placer assembly 22 continues to move the carrier 24 and shuttle 26 in the upper direction 188 until the shuttle 26 is properly received within the upper portion 166 of the receiver 28, such that the pneumatic output ports 123, 125 are properly aligned with the pneumatic ports 168, and the electrical output connector 127 is properly aligned with the electrical port 170 of the receiver 28, thereby pneumatically and electrically coupling the towed vehicle with the towing vehicle. The controller then operates to move the pneumatic cylinders 114 in an inward direction 190 such that the springs 148 bias the hook 144 of each clamping arm 140 into engagement with one of the reliefs 169 of the side walls 156 of the carrier 24. The placer assembly 22 is then actuated in a downward direction 192 until the carrier 24 is free of the receiver 28, and returns the carrier 24 to a storage position during operation of the associated vehicle.

Uncoupling of the trailer from the towing vehicle is completed in a reversed but similar manner. As best illustrated in FIGS. 10A-10D, the placer assembly 22 moves the carrier 24 in the upper direction 188 until the carrier 24 is properly aligned with the shuttle 26. The pneumatic cylinders 114 are then actuated in the outward direction 176, thereby overcoming the biasing force exerted by the springs 148 on the clamping arms 140 and disengaging the hook 144 of each clamping arm 140 from the associated relief 169. The placer assembly 22 then is actuated in the downward direction 192, thereby removing the shuttle 26 from within the receiver 28.

The above description is considered that of the preferred embodiments only. Modifications of the embodiments disclosed herein will occur to those skilled in the art and to those who make or use the disclosed embodiments. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and not intended to limit the scope of the invention, which is defined by the following claims as interpreted according to the principles of patent law, including the doctrine of equivalents.

In the foregoing description, it will be readily appreciated by those skilled in the art that modifications may be made to the described embodiments without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise. 

1. An automated trailer coupling arrangement, comprising: a receiver member configured to be supported on a towed vehicle and including a first pneumatic coupler and a first electrical coupler; a shuttle member including a second pneumatic coupler configured to couple to a pneumatic supply source of a towing vehicle, and a second electrical coupler configured to couple to an electrical supply source of the towing vehicle; and a control arm assembly configured to be supported on a towing vehicle, comprising: a carrier member configured to operably couple and uncouple with the shuttle member; an actuator coupled to the carrier member and configured to move the carrier member between a first position where the carrier member is coupled with the shuttle member and the shuttle member is spaced from the receiver member, and a second position where the second pneumatic coupler is coupled with the first pneumatic coupler and the second electrical coupler is coupled with the first electrical coupler and the carrier member is uncoupled and spaced from the shuttle member.
 2. The automated trailer coupling arrangement of claim 1, wherein the receiver member includes a third pneumatic coupler and the shuttle member includes a fourth pneumatic coupler, and wherein the third pneumatic coupler is uncoupled from the fourth pneumatic coupler when the carrier member is in the first position, and the third pneumatic coupler is coupled from the fourth pneumatic coupler when the carrier member is in the second position.
 3. The automated trailer coupling arrangement of claim 2, wherein the shuttle member includes a first pneumatic input port pneumatically coupled to the pneumatic source and to the first pneumatic coupler, and a second pneumatic input coupled to a to the pneumatic source and to the third pneumatic coupler.
 4. The automated trailer coupling arrangement of claim 1, wherein the actuator of the control arm assembly includes a pneumatic cylinder arrangement configured to move the carrier member between the first and second positions.
 5. The automated trailer coupling arrangement of claim 1, wherein the receiver includes a housing configured to receive at least a portion of the shuttle member therein.
 6. The automated trailer coupling arrangement of claim 5, wherein the housing defines a first receiver portion having a first width and a second receiver portion having a second width that is less than the first width, and wherein the first receiver portion is configured to guide the carrier member from the first receiver portion to the second receiver portion as the carrier member moves from the first position toward the second position.
 7. The automated trailer coupling arrangement of claim 6, wherein the first receiver portion includes a pair of angled sidewalls.
 8. The automated trailer coupling arrangement of claim 1, wherein the carrier member includes a clamp arrangement moveable between a clamped position where the carrier member is coupled to the shuttle member and an unclamped position where the carrier member is uncoupled from the shuttle member, and wherein the clamp arrangement is biased by a biasing member toward the clamped position.
 9. The automated trailer coupling arrangement of claim 1, further comprising: a controller operably coupled to the control arm assembly and configured to move the carrier member between the first and second positions.
 10. The automated trailer coupling arrangement of claim 9, wherein the controller is operated by an operator remotely located from the trailer coupling arrangement.
 11. The automated trailer coupling arrangement of claim 1, wherein the control arm assembly includes a four-bar linkage assembly.
 12. The automated trailer coupling arrangement of claim 11, wherein at least one linkage of the four-bar linkage assembly is adjustable between a first length and a second length that is less than the first length.
 13. The automated trailer coupling arrangement of claim 12, wherein the at least one linkage is biased from the first position toward the second position.
 14. An automated trailer coupling arrangement, comprising: a receiver member configured to be supported on a towed vehicle and including a first pneumatic coupler, a second pneumatic coupler and a first electrical coupler; a shuttle member including a third pneumatic coupler pneumatically configured to be coupled to a pneumatic supply source of a towing vehicle, a fourth pneumatic coupler pneumatically configured to be coupled to the pneumatic supply source, and a second electrical coupler configured to be coupled to an electrical supply source of the towing vehicle; a control arm assembly supported on a towing vehicle, comprising: a carrier member configured to operably couple and uncouple with the shuttle member; and an actuator coupled to the carrier member; wherein the control arm assembly is moveable between a first position where the carrier member is coupled with the shuttle member and the shuttle member is spaced from the receiver member, a second position where the shuttle member is received within the receiver member and is coupled to the carrier member, a third position where the shuttle member is received within the receiver member and the first and second pneumatic couplers are pneumatically coupled with the third and fourth pneumatic couplers, respectively, and the first electrical coupler is coupled with the second electrical coupler, a fourth position where the carrier member is uncoupled from the shuttle member and abuts the shuttle member, and a fifth position where the carrier member is uncoupled and spaced from the shuttle member; and a controller operably coupled to the control arm assembly and configured to move the carrier member between the first, second, third, fourth and fifth positions.
 15. The automated trailer coupling arrangement of claim 14, wherein the control arm assembly is configured to be coupled to the towing vehicle such that the carrier member is moveable in a lateral direction relative to a longitudinal direction of travel of the towing vehicle as the carrier member is moved between the first and second positions of the carrier member.
 16. The automated trailer coupling arrangement of claim 15, wherein the actuator of the control arm assembly includes a pneumatic cylinder arrangement configured to move the carrier member between the first and second positions.
 17. The automated trailer coupling arrangement of claim 14, wherein a housing of the receiver member includes a first receiver portion having a first width and a second receiver portion having a second width that is less than the first width, and wherein the first receiver portion is configured to guide the carrier member from the first receiver portion to the second receiver portion as the carrier member moves from the first position toward the second position.
 18. The automated trailer coupling arrangement of claim 17, wherein the first receiver portion includes a pair of angled sidewalls.
 19. The automated trailer coupling arrangement of claim 14, wherein the carrier member includes a clamp arrangement moveable between a clamped position where the carrier member is coupled to the shuttle member and an unclamped position where the carrier member is uncoupled from the shuttle member, and wherein the clamp arrangement is biased by a biasing member toward the clamped position.
 20. The automated trailer coupling arrangement of claim 14, wherein the control arm assembly includes a four-bar linkage assembly.
 21. The automated trailer coupling arrangement of claim 20, wherein at least one linkage of the four-bar linkage assembly is adjustable between a first length and a second length that is less than the first length.
 22. The automated trailer coupling arrangement of claim 21, wherein the at least one linkage is biased from the first position toward the second position.
 23. The automated trailer coupling arrangement of claim 14, wherein the control arm assembly is configured to be pivotably coupled to the towing vehicle such that the carrier member is moveable in a lateral direction relative to a longitudinal direction of travel of the towing vehicle.
 24. The automated trailer coupling arrangement of claim 14, wherein the actuator includes a linkage having an overall length that is changed as the control arm assembly is moved from the first position to the second position and the carrier member abuts the receiver member.
 25. A method for operating an automated trailer coupling arrangement, comprising: providing a receiver member supported on a towed vehicle and including a first pneumatic coupler and a first electrical coupler; providing a shuttle member including a second pneumatic coupler pneumatically coupled to a pneumatic supply source of a towing vehicle, and a second electrical coupler coupled to an electrical supply source of the towing vehicle; providing a control arm assembly coupled to a towing vehicle, comprising: a carrier member configured to operably couple and uncouple with the shuttle member; and an actuator coupled to the carrier member, and configured to be supported from the towing vehicle; and coupling the shuttle member to the receiver member by moving the control arm assembly from a first position where the carrier member is coupled with the shuttle member and the shuttle member is spaced from the receiver member, to a second position where the shuttle member is received within the receiver member and is coupled to the carrier member, to a third position where the shuttle member is received within the receiver member and the first pneumatic coupler is pneumatically coupled with the second pneumatic coupler, respectively, and the first electrical coupler is coupled with the second electrical coupler, to a fourth position where the carrier member is uncoupled from the shuttle member and abuts the shuttle member, to a fifth position wherein the carrier member is uncoupled and spaced from the shuttle member.
 26. The method of claim 25, further comprising: providing a controller operably coupled to the control arm assembly; and controlling the control arm assembly between the first, second, third, fourth and fifth positions via the controller.
 27. The method of claim 25, wherein the control arm assembly is coupled to the towing vehicle such that the carrier member is moveable in a lateral direction with respect to a longitudinal direction of travel as the control arm is moved from the first position to the second position.
 28. The method of claim 25, wherein the actuator includes a linkage having an adjustable length, and wherein the length of the linkage is changed as the control arm assembly is moved from the first position to the second position. 